Patients at the highest risk for lung cancer derived considerable benefit from low-dose CT screening, but the screening method prevented very few deaths among patients at lowest risk for the disease, according to study results.

“These findings provide empirical support for risk-based targeting of smokers for such screening,” the researchers wrote.

Previous findings from the National Lung Screening Trial indicated that screening with low-dose CT was associated with a 20% decrease in mortality from lung cancer compared with chest radiography, according to background information provided in the study. However, observational data are lacking for risk-based lung cancer screening, researchers wrote.

In the current study, researchers set out to assess whether the benefits of low-dose CT screening in patients included in the National Lung Screening Trial varied depending upon prescreening risks for lung cancer mortality.

“Across risk groups for lung cancer death, we evaluated the effect of low-dose computed tomography screening on the number of prevented lung cancer deaths, the number of participants with false-positive results, and the number of participants who would need to be screened to prevent one lung cancer death,” they wrote.

Within the CT screening group, the number of prevented deaths associated with lung cancer per 10,000 person-years increased according to risk quintile:

0.2 for quintile 1;

3.5 for quintile 2;

5.1 for quintile 3;

11 for quintile 4; and

12 for quintile 5 (P=.01 for trend).

Researchers noted “significant decreasing trends in the number of participants with false-positive results per screening-prevented lung cancer death” across risk quintiles:

“Although there is currently a consensus among published screening guidelines on recommending low-dose computed tomography screening for patients who meet the National Lung Screening Trial entry criteria, some experts have speculated that further refinement of selection criteria may be appropriate,” the researchers wrote. “Our results confirm that tailoring of low-dose computed tomography screening to a patient’s predicted risk of lung-cancer death could narrow the National Lung Screening Trial-eligible population without a loss in the potential public health benefits of screening or a disproportionate increase in the potential harms.”